In general, generating a steering force in a vehicle, a steering system uses power to reduce the operational force, smoothly transmit the operational force and allow rapid steering.
Further, a tilt structure that allows tilting the steering wheel and a telescopic structure that allows adjusting the position of the steering in the axial direction of the steering column are mounted to the steering column in the steering system for the convenience of a driver such that the driver can adjust the position of the steering wheel in accordance with his/her body shape for more comfortable driving.
These functions for more comfortable driving are generally achieved by a tilt lever assembly disposed at the lower portion of the steering column. In detail, a distance bracket is disposed inside a tilt bracket covering the steering column and a tilt lever is fastened to a side of the tilt bracket by a tilt bolt, in which as the tilt lever actuated, a pressing force is applied to the tilt bracket or a pressing force exerted on the tilt bracket to the distance bracket is released by movement of a cam, such that tilt and telescopic operations are achieved.
A mechanism having the above configuration should meet predetermined requirements in accordance with vehicle safety regulations about driver's knees injury rate by the tilt lever disposed at a side of the steering column when the knees move to the steering column in a car crash, particularly it is required to remove cause of demerit for the knees injury rate in accordance with EURO NCAP that is one of European car safety performance assessment programme. That is, in testing knees injuries due to collision of knees and a rigid body in accordance with the car safety performance assessment programme, high injury rate is a cause of demerit, thereby decreasing the car safety performance.
However, the tilt lever that allows comfortable driving is commonly disposed at the lower portion of the steering column, such that even though the steering column is covered, a part of tilt lever is exposed and the mechanism necessarily has a structural vulnerability in that driver's knees are not safe in a car crash.
Further, the tilt lever is commonly made of steel and disposed at the lower portion of a side of the steering column, such that it causes concentrated load and becomes a cause of demerit in measuring knees injury rate in accordance with EURO NCAP.
Accordingly, an airbag, for knees is provided over the exposed part of the tilt lever, but this configuration increases cost and weight and is difficult to be practically applied to vehicles.
In addition, since the tilt lever commonly pivots about a hinge shaft, the rotational angle of the tilt lever is limited to about 40° or less by interference with a crash pad lower panel in operation (rotation) and operational quality is deteriorated by the limit on the rotational angle of the tilt lever.
Further, since the tilt lever is disposed at the lower portion of a side of the steering column, it is difficult to secure visibility in operation and operational position is bad, which also deteriorates the operational quality.
The information disclosed in this Background of the Invention section is only for enhancement of understanding of the background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art that is already known to a person skilled in the art.